Main Mechanism and Influencing Factors of Earthquakes Induced by Hydraulic Fracturing for Shale Gas Exploitation
With the development and application of hydraulic fracturing technology,the seismic activity in shale gas mining areas in various regions has obviously increased especially those above moderate level,seriously affecting industrial and human activities.In order to ensure safe and green shale gas exploitation and avoid or reduce destructive seismic activity,it is of great significance to study the mechanism and influencing factors of hydraulic fracturing induced earthquakes.By summarizing the seismic activity characteristics of typical shale gas mining areas in the United States,Canada and China,and combining fault mechanics and Coulomb-Mohr failure criteria,this paper systematically sorts out the main mechanisms and the influencing factors of hydraulic fracturing induced earthquakes.The conclusion and analysis show that injection-induced seismicity can be explained macroscopically based on Coulomb-Mohr criterion,and the changes of friction coefficient of a fault,normal stress,shear stress and pore pressure in reservoir area can affect the occurrence of induced seismicity.From the relative relationship between faults and induced earthquakes,there are three possible mechanisms:the first is the fault activation caused by pore pressure change,the second is the fault activation caused by pore elasticity effect,and the third is the fault activation caused by aseismic slip.Induced seismicity is not only related to fluid injection parameters,but also depends on conditions such as seismogenic background and stress state of regional faults.At present,due to the incomplete factors affecting the initiation and propagation of fault shear fracture under hydraulic fracturing,and the lack of strong experimental verification,it is necessary to carry out hydraulic fracturing experiments to simulate the conditions such as fluid loading and stress boundary during shale gas production,and further determine the driving mechanism and key influencing factors of fault shear fracture.
Induced earthquakeMechanisms of occurrenceHydraulic fracturingShale gas exploitation
万方数据
维普
